Portable light tower



Feb'. 17, 1.970 I Q v DEBELL' 'Y 3,495,364

PORTABLE LIYGHT' TOWER f Filed May 25. 196'? 4 sheets-Sheet- 1 Feb. 17,1970 G. v. lar-:BELLA oRTABLELIGHT TOWER 4 Sheets-Sheet Filed May 25,1967 Y PORTABLE LIGHT TOWER Filed May 25, 1967 4 Sheets-Sheet 5 bwl/vra@WWMC Feb. 17, 1970 G. V.`DEBE|.| A

PORTABLE LIGHT TOWER 4 SheebS-Shet 4 Filed May 25. 1967K #fromm/5 UnitedStates Patent O 3,495,364 PORTABLE LIGHT TOWER Gasper V. De Bella, LosAltos, Calif., assignor to Cal- West Electric, Inc., a corporation ofCalifornia Filed May 25, 1967, Ser. No. 641,374 Int. Cl. E04h l 2/ 34U.S. Cl. 52 121 1 'Claim ABSTRACT OF THE DISCLOSURE A light tower on aportable carriage provided with a lighting generator has asuperstructure with a telescoping mast pivoted thereon to turn fromhorizontal to vertical position about an eccentric axis. The mast may beextended and retracted by a cable winch and erected and lowered byanother cable winch, the lowering motion being controlled by a hydrauliccylinder and piston mechanism. Steadying legs and various positionalinterlocks are provided.

My invention relates to devices which include a source of electricalenergy and are mobile to carry a light source connected to the energysource to any suitable location for use in augmenting the illumination,particularly for night construction work, illumination of special areasfor security and in comparable environments. A device of this generalnature is disclosed in my copending application entitled Light Tower ledJan. 19, 1967 with Ser. No. 610,427. In portable light towers it iscustomary to provide an extensible mast carrying lighting elements whichcan be moved to a substantial distance above the transport carriage bymeans of a pivotal mounting of the supporting mast, so that duringtransport the mast can be carried about horizontally and for use can beerected to a vertical position. The lighting elements at the free end ofthe mast are relatively heavy and massive. In moving the mast to itslower, generally horizontal position from its upright, erected positionthere is Some danger that the illuminating units and even the mastitself may receive undue shocks and may be damaged.

It is therefore an object .of this invention to provide a protable lighttower arranged in such a way that a movable mast can be controlled inits operation so as to avoid damaging shocks.

Another object of the invention is to provide a portable light towerhaving a number of interlocks so that the movable portion will notreadily be dislodged, but will be readily and easily retained inappropriate position subject to the operators control.

Another object of the invention is to provide a portable light tower inwhich a stable platform for the tower is provided when it is not beingtransported.

Another object of the invention is in general to provide an improvedportable light tower.

Other objects together with the foregoing are attained in the embodimentof the invention described in the accompanying description andillustrated in the accompanying drawings, in which:

3,495,364 Patented Feb. 17, 1970 ICC FIGURE l is a side elevation of aportable light tower constructed pursuant to the invention, the towerbeing shown at a stationary location with the mast erected;

FIGURE 2 is a side elevation similar to FIGURE 1 but to an enlargedscale and with the tower in its rest or retracted position;

FIGURE 3 is an end elevation of the structure as shown in FIGURE 2;

FIGURE 4 is a detail cross section, the plane of which is indicated bythe line 4 4 of FIGURE 1;

FIGURE 5 is a detail showing in plan one of the steady legs utilized onthe carriage frame, the plane of section being indicated by the line 5 5of FIGURE l;

FIGURE 6 is for the most part a side elevation with portions in sectionshowing one end of the mast in transport position;

FIGURE 7 is a view similar to FIGURE 6 but showing the mast raisedsomewhat from transport position;

FIGURE 8 is a cross section, the plane of which is indicated by the line8 8 of FIGURE 6;

FIGURE 9 is a plan, the plane of the view being indicated by the line 99 of FIGURE 7; and

FIGURE l0 is a longitudinal or axial cross section through a portion ofthe mast showing a detent mechanism utilized in connection therewith.

In its prefeured form, my portable light tower includes a carriage 6incorporating a frame 7 supported on the ground by ground-engagingwheels 8 and having a hitch 9 to secure the carriage to a tow vehicle.When the car riage is not being advanced, it can rest temporarily on theground without support by the tow vehicle by reason of a support leg 11which can be moved upwardly out of the way during transport or swungdownwardly for temporary ground rest. If the carriage is to be supportedon the ground with better stability, then the user may ernploy any oneor more of a number of steady legs 12 disposed at appropriate locationson the frame 7.

A steady leg as shown, for example, in FIGURE 5 includes a swinging arm13 connected to the fra-me 7 by a vertical pivot pin 14. The steady legswings between a stowed position, represented by the dotted lines inFIG- URE 5, wherein it can be retained within a clip 16 by a removablepin 17 and an active position as shown by the full lines in FIGURE 5.The horizontal arm 13 adjacent one end carries a swivel pad 18 from`which a screw leg 19 can be extended so as to position a bottom pad 21in appropriate contact with the ground. The swivel pad 18 is retainedeither in its ground-engaging position or in a retracted position bymeans of a spring-pressed pin 22 engaging the respective one ofappropriate aperture 23 in the arm 13. In active position the arm 13 isheld by a retaining bracket 24 against the frame by -means of aretaining pin 25. In this fashion the weight on -the carriage 6, ifdesired, can be partly or entirely transferred to and supported on thesteady legs.

On the frame 7 adjacent forward end thereof is an upright superstructure26 comprised of appropriate shapes provided with braces 27 and formed tosupport a pair of journals 28 and 29 carrying a cross shaft 31 designedfor pivotal movement about a transverse, horizontal axis. Adapted toengage the shaft 31 is a yoke 32 arranged to be secured to and encompassthe lower tube 33 of an extensible mast 34. The longitudinal axis 36 ofthe mast is eccentric to or displaced from one side of the axis of theshaft 31. At its lower end lthe tube 33 carries a platform 37 having anextension 38. A retaining pin 39 engages the extension 38 with thesuperstructure so as to hold the mast in an upright position. When thepin 39 is temporarily Withdrawn against ythe urgency of its spring, theeccentric mast is free to swing about the axis of the shaft 31.

Also connected to the platform 37 is a cable 41 eX- tending to ahand-operated winch 42 mounted on the frame 7. Operation of the winch 42is effective to move the mast from a generally horizontal, rest positionto a substantially vertical, active position. As the mast is disposedeccentrically with respect to the pivot shaft 31, it can readily beerected by tension on the cable 41 and can be restored to rest positionby paying out the cable 41. The motion of the mast is preferably movedvery carefully, particularly during the latter part of its travel towardrest position, by special means for controlling the lowering movement.For that reason, the yoke 32 has an extended arm 44 on the opposite sideof the shaft 31 from the mast and engaging the upper end of ahydraulically expansible chamber 46 by means of an upper pivotconnection 47. The lower end of the hydraulic chamber is connected by apivot 48 to the superstructure.

The hydraulic mechanism includes an outer cylinder 51 and an interiorpiston (not shown) connected to a piston rod 52. The opposite ends ofthe chamber are interconnected by a suitable duct 53 allowing freehydraulic flow from one end of the cylinder to the other except for theinterposition of an adjustable check arrangement 54. This permits readyow from one end to the other of the cylinder during the upward orerecting movement of the mast but partly shuts off and throttles to anyadjusted extent the hydraulic flow in the other direction when the mastis being moved Ifrom its upright toward its rest position. If the loadon the mast in so moving is at any time let go by the cable 41, thehydraulic mechanism is effective to retard the return movement of themast to any speed well within any selected value.

The mast includes not only the lower tube 33 but likewise includes anumber of intermediate tubes 61, 62 and 63, for example, interrelatedfor telescoping movement under the influence of a winch y64 mounted onthe platform 37 and manually operated to lift the various mast sectionswith respect to each other, all as disclosed in my above-identified,copending application. When the tubular sections are extended withregard to each other, they are held in position by the winch 64. Theymay also be held by a friction detent 66 (FIGURE 10). This is aneccentric rotor 67 pivotally mounted between ears 68 on the tube 61 andis normally urged by a spring 69 into engagement with an inner tube sothat axial movement of the inner tube toward lower position causes africtional snubbing action. This prevents the downward movement of theinner tube. A manually controlled chain 71 is afforded for releasing thedetent 67 from engagement with i the tube to allow free sliding movementthereof.

At the upper end the inner tube 63 merges with a sleeve 72 arranged witha generally horizontal axis. Since the inner tube is rotatable about itslongitudinal axis, the sleeve 72 can be rotated about the mast axis toany extent desired. Relative rotation may be held or limited, however,by a set screw 73 mounted in a collar 74 on the non-rotatable tube 62and encompassing the upper end of the inner tube 63, the set screw beingturned by a handle 76 so as to move from clamping position to releasingposition and vice versa. The sleeve 72 is designed in its rest positionto lie within an arcuate trough 77 disposed at the upper end of anupright brace 78 connected to the frame 7 adjacent the rearward endthereof. The trough is extended to provide a tangent lock plate 79through an opening in which a plunger 81 is movable under control of aspring 82 and of a yoke lever 83 connected by a pivot 84 to the plate79f A handle 86 projects from the yoke to rock the yoke about the pivot84. A latch lever 87 is connected by a pivot 88 to the yoke and can beengaged with a mounting bracket 89 extending from the plate 79 andserving as a base for the spring 82. With this mechanism, the plunger 81can be retracted and latched by manipulation of the handle 86 andengagement of the latch lever 87 with the frame 89. When the latch 87 israised, the spring 82 is effective to project the plunger 81 and restorethe handle 86. When projected, the plunger 81 extends forwardly into aneye plate 90 upstanding from the sleeve 72 and is thus effective to holdthe sleeve and the mast in rest position partly supported in the cradle77.

Extending rotatably through the sleeve 72 is a cross bar 91symmetrically mounted and having a cylindrical central portionjournalled within the sleeve 72. Relative rotation, however, is limitedby a holding pin 92 radially movable by a spring 93 and a T handle 94.When the detent pin 92 is projected, as shown in FIGURE 7, itinterengages the sleeve 72 and the cross bar 91 and precludes rotationthereof about a longitudinal axis. When the handle 94 is withdrawn, thecross bar may be rotated within the sleeve. The limit of rotation isparticularly established by a central projection 96 extending from thesleeve 72 in the path of rotation of lugs 97 and 98 projecting from theopposite sides of the cross bar, thus limiting the rotational motion toapproximately degrees.

The cross bar can be provided with any of several differentinstrumentalities. In this instance it carries a plurality of lightingsources 101 of a standard kind. These have movable mountings 102connecting them to the cross bar. The lighting units 101 are supplied byconductors 103 connected through cables 104 to a suitable lightingmotor-generator set 106 on the frame 7. When the tower or mast iserected, the various light units can be turned on and can be oriented invirtually any desired manner to illuminate a selected zone.

In the operation of this structure, the hitch 9 is secured to a draftvehicle. The various support or steady legs are in withdrawn positionand the mast is collapsed and is anchored in its rest position. Themechanism is then transported to any desired site. The draft vehicle canthen be unhitched, at least temporarily, and the support 11 can beutilized. If the location is to be occupied for a protracted time or ifspecial leveling is required, the various steady legs are swung out,erected and locked and cranked into position. The winch 42 is actuatedafter release of the latch pin 81 and the mast is erected and locked inits upright position. Then the winch 64 is actuated to project thevarious mast sections. These are held in extended position. Prior toerecting the mast fully or shortly after it has left its cradle, asshown in FIGURE 7, the lighting elements can be oriented as desired.This may involve appropriate rotation of the cross bar 91 and of thesleeve 72. The lights in their upright position can then be utilized asdesired.

When the structure is to be put out of use, the detent 66 is releasedand the various mast tubes telescope by gravity into each other. Thewinch 64 can assist in regulating the lowering movement. Then thelocking pin 39 is withdrawn and the mast, since it is eccentric, ispermitted to swing downwardly by its own weight. Excessive speed isprecluded by the hydraulic mechanism 46 so that the mast is cushionedinto its cradle or trough 77. It is then latched in position fortransport. After the draft vehicle is connected, the steady legs andother supports are withdrawn and the device is drawn to a new location.

What is claimed is:

1. A portable light tower comprising a carriage, a superstructure onsaid carriage, a transverse shaft journalled on said superstructure, amast on one side of said shaft, a yoke connected to said mast and tosaid shaft, an arm secured to said shaft and projecting therefrom on theside away from said yoke, means interconnecting said mast and saidcarriage for moving said mast about the 6 aXis of said shaft andrelative to said superstructure be- FOREIGN PATENTS tween a restposition and an active position, a hydraulic 866,223 4/1961 GreatBritain.

cylinder at one end pivoted to said arm, a hydraulic piston reciprocablein said cylinder and at one end pivoted NORTON ANSHER Primary Examinerto said superstructure, a by-pass duct extending from one end of saidcylinder to the other end thereof, and means 5 LEO H' MCCORMICK JR"Assistant Examiner in said duct for regulating hydraulic flowtherethrough.

References Cited UNITED STATES PATENTS 3,055,459 9/1962 Eitel 52-121 XR3,381,118 4/1968 Widner 640-3 U.S. C1. X.R.

